For our company we first move items to resolved while we are waiting for a release and then after the release we move all resolved tickets to Closed. Is there some kinda of automation that can be used to close these tickets after their fixVersion is released?

But before you start writing your plugin maybe you need to change your company procedure in regards to closing issues. Usually programmers resolve an issue and a person who created an issue closes it after testing. Here is a good discussion about close vs resolve - http://stackoverflow.com/a/4718505/941776. Is there a particular need to close issues when they are released?